1. Field of the Invention
The present invention relates to an image forming system, a reading apparatus and an image forming apparatus.
2. Description of Related Art
Conventionally, there have been known image forming systems including electrophotographic image forming apparatuses which provide toners to recording media such as sheets of paper and fix the toners to form images and reading apparatuses which read the images that were formed on the recording media by the image forming apparatuses. In such image forming systems, the image forming apparatuses form predetermined identification marks on recording media and the reading apparatuses read the predetermined identification marks so that the reading results can be used for various purposes. For example, information according to the position of an image formed by an image forming apparatus can be obtained by reading identification marks with a reading apparatus and calculating the positions of the identification marks on the recording medium. By feeding back the information to the image forming apparatus and correcting the image forming position with the image forming apparatus, the image can be formed at an appropriate position on the recording medium.
For example, Japanese Patent Application Laid Open Publication No. 2014-232141 discloses a technique of making the respective image forming positions on the front surface and the back surface of a recording medium match each other by calculating the register mark positions as the identification marks formed on the surface of the recording medium from the reading result by the reading apparatus, and correcting the image forming position on the back surface by the image forming apparatus on the basis of the register mark positions.
However, conventional image forming systems have had a problem that, when the color of recording medium is approximate to the color of identification marks recorded on the recording medium, the identification marks are difficult to distinguish from the recording medium on the basis of the reading result by the reading apparatus, and thus, the accuracy in calculating the positions of identification marks based on the reading result is lowered and the identification marks cannot be detected.